The invention is directed to a method for the identification of persons with ultrasound.
U.S. Pat. No. 4,564,019 discloses a method for the measurement of characteristics of living tissue by ultrasound. DE 4 226 865 A1 discloses an ultrasound diagnostics apparatus for dermatology.
Imaging methods for the recognition of the ridge structure of skin surfaces are disclosed by U.S. Pat. No. 5,224,174 and WO 95/12354.
U.S. Pat. No. 4,977,601, EP 0 619 095 A1, U.S. Pat. No. 5,218,644, U.S. Pat. No. 5,258,922, EP 0 402 779 A2 and WO 94/24937 disclose methods that utilize the amount of the spatial frequency spectrum of the ridge structure or of other cell structures ("epithelium structure") not described in greater detail in the applications. These structures are acquired by a transducer section and are averaged over a plurality of transducer sections for the identification of persons.
WO 94/010434 discloses a method that combines ultrasound waves with electromagnetic waves.
WO 95/06262 discloses a method that works with inverse excitation.